Advanced Medical Electronics proposes to develop an ultra low power wireless electrocardiograph sensor for use in ambulatory electrocardiographs (ECGs). Ambulatory ECG products include traditional Holter recorders, cardiac arrhythmia event loop recorders, and recently introduced telemetry-enabled cardiac monitors that utilize cellular phone networks to provide live or semi-live periodic data transfers to monitoring facilities. Ambulatory ECG studies are an important component in the field of cardiac diagnostics. Health outcomes for rural and underserved communities including American Indians can be improved with culturally specific interventions and careful health care monitoring and management utilizing new and improved technologies. Many barriers prevent American Indians and Alaska Natives living on reservations from achieving adequate healthcare resources. Remote diagnostic tools equipped with telehealth monitoring solutions can help remove some barriers to adequate healthcare delivery. Important barriers such as proximity to healthcare facilities and limited transportation options can be reduced by using remote diagnostic techniques provided that the technology solutions are simple enough for patients to successfully obtain diagnostic results. In this project we propose an advanced ultra-miniature long life wireless ECG sensor. By utilizing recently developed ultra low power radio, microprocessor, and other electronics technologies we propose to substantially reduce the size and lower the power of the ECG sensor to enable more comfortable wearable devices and eliminate the need for patients to replace the batteries. We hypothesize that these improvements will improve health outcomes, lower overall study costs by reducing the number of required batteries, improve the rate of successful studies by eliminating the required patient action of battery replacement in the home, and provide more efficient processing of devices for reuse by eliminating the difficult-to-clean user operable battery compartment on the sensor.